P D.....Thanks for that accolade. Nice to know it did some good. Picture looks like a later "Big Journal" Crank But you cannot relax. The next trial is to come. What you think is a choked oilway is in fact a removable tube. Removable? Well in a manner of speaking. One sludge trap plug has a small central pip to seal the end of the tube. The tube bells out at the other end, where the oil goes in. The tube is located by the radial flywheel securing bolt. Once this is removed, the tube will come out, revealing even more sludge. Like the plugs, some are easy, some have to be carefully drifted out, or cut down the middle with a small hacksaw blade and collapsed inwards.
Many folks have neglected to remove the tube for cleaning, leaving that sludge there to do its worst. Take your time and do it properly. Lots of information about re assembly on this forum. Some people change the flywheel bolts as here failure can also make it go bang.
The earlier small journal crank is much simpler, just remove the plugs and clean everything.
Note which way the Conrods are fitted. Cap and rod numbers should match on each rod. Matched rods are usually from the same batch, so the numbers stamped on them will be in the same style and close, rarely consecutive. Forging numbers also will be in the same font if they are matched original rods. For a big journal rod, the forging number is 67-1160.
Opinion is that the rods are fitted with the numbers to the gearbox side, shell bearing locating tabs to the front of the engine.
The left hand, drive side rod has a small hole from the bearing location to the bottom of the side of the rod. This should point towards the flywheel.
See postings headed "Conrod Oil hole" for a bit more about this true purpose of this hole.
Apologies if you know all of this this already, but if the previous owner couldn't match bores to pistons, even the basic assembly may be incorrect.
Good to know you have made a start.
Keep Spannering
Swarfy.